** One of the individually-numbered reports issued solely to members of the Western Allies intelligence community with appropriate security clearance. Suppressed and withdrawn from further circulation for security reasons.

** The July 1945 report by L.G. Taffs on behalf of BIOS containing, inter-alia, details of the supersonic wind-tunnel at Kochel and the facilities for the assembly and static testing of V2 rockets at Redl Zipf.

In lovely condition, as issued, in original stapled card wrappers, protected in a modern clear archival jacket.

Germany's wartime aeronautical engineering efforts were greatly accelerated by their advances in high-speed wind-tunnel technology, an area in which they were far in advance of anything produced by the Americans. By the end of the war, Germany had at least three different supersonic wind tunnels, with one capable of Mach 4.4 (heated) airflows.

In view of the subject matter, indisputably amongst the most important of the BIOS reports. Classified as 'SECRET', quickly suppressed.

A search through COPAC and WorldCat failed to reveal a record of an example being held by any national, regional, or specialist library anywhere in the world.